<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      box-sizing: border-box;
    }
    body {
      display: flex;
      flex-direction: column;
      align-items: center;
      background-color: #efedd6;
      margin: 0;
      font-family: 'Roboto', sans-serif;
    }
    .box {
      display: flex;
      justify-content: center;
      align-items: center;
      width: 400px;
      height: 200px;
      color: #fff;
      background-color: steelblue;
      margin: 10px;
      border-radius: 10px;
      box-shadow: 2px 4px 5px rgba(0, 0, 0, 0.3);
      transform:  translateX(-400%);
      transition: transform 0.4s ease;
    }
    .box:nth-child(even) {
      transform:  translateX(400%);
    }
    .box.show {
      transform: translateX(0);
    }
    .box h2 {
      font-size: 45px;
    }
  </style>
</head>
<body>
  <h1>Scroll to see the animation</h1>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>
  <div class="box"><h2>Content</h2></div>

  <script>
    const boxs = document.querySelectorAll(".box");

    window.addEventListener("scroll", checkBoxs);

    checkBoxs();

    function checkBoxs() {
      const triggerBottom = window.innerHeight / 5 * 4;

      boxs.forEach(box => {
        let boxTop = box.getBoundingClientRect().top;
        if(boxTop < triggerBottom) {
          box.classList.add("show");
        }else{
          box.classList.remove("show")
        }
      });
    };
  </script>
</body>
</html>